Exterminators in the N.O. area - large rodents in the attic (3-month update: Rats gone!)

Squirrels and rats could fit in through the gable vent (slats too far apart, though no damage or missing piece visible).
One happy find, once we got up on a ladder, was that the gable vent actually was blocked off with a grate. Just that we couldn't see the grate from the ground. So the spot I assumed was the entry point was actually already sealed off.